The invention relates to the field of bicycles and in particular to a pedal powered unit with separate drive chains for each of the pedals to allow for continuous shifting as well as a more horizontal position for the user""s legs. The invention can also be used in tricycles with only minor modifications.
The invention also describes new and improved methods for shifting for power and speed as well as a hand pedaling arrangement to allow for supplemental power to be supplied by the arms of the driver. The invention also provides for a lowered seating arrangement that allows the maximum force of the leg muscles to be exerted on the pedals of the bicycle.
Most present cycling designs provide for the driver to exert the force on the pedal by pushing downward with the legs. This is helped somewhat by the driver standing up in the bike, holding onto the handle bars and then using the force of gravity, etc. to exert more force on the pedals. However, such methods are inadequate when compared with the amount of force that can be generated by the legs when a person is in the horizontal sitting position and braces his back against a strong support and uses his legs to exert pressure in the horizontal direction. This position will greatly increase the amount of force that can be generated upon the pedals of the bicycle. Such gain is likely to be in the neighborhood of several hundred pounds of torque.
Conventional bicycle designs provide for cycling motion of the pedals. This results in only a very narrow window in which the user can exert the most power from his legs. In such case, the user""s power is very ineffective at the top of the cycle, i.e. with the pedal at the top or at 0xc2x0 (180xc2x0 being when the pedal is at the bottom of the cycle). The user""s power remains ineffective until the pedal reaches about 30-40xc2x0 from the top. The best power range for conventional cyclic pedaling is between 40xc2x0 and 140xc2x0. This amounts to 100xc2x0 of power out of the 180xc2x0 or so when the legs are actually pushing downward (i.e. from 0xc2x0 to 180xc2x0 constitutes the down stroke for purpose of discussion).
The rest of the cycle, the other 180xc2x0 is when the cycle is returning back up and thus the user is not using the legs in this half of the cycle. After the power part of the stroke is over, the user must then use part of his power to return his foot on the pedal another 180xc2x0 back to where it will again be in position to exert power on the down stroke.
The applicant""s invention by contrast allows for straight line strokes of the pedals and hence the legs can exert the maximum amount of force throughout very nearly the entire length of the power stroke, i.e., on the forward part of the stroke. Hand pedaling arrangements of the type described herein can be use with the horizontal seating arrangement described.
Thus the bicycle drive designs described in the present invention are designed for best use with the driver in a horizontal seating position although different seating arrangements are possible without varying from the spirit of the invention.
A system for powering bicycles using drive chains that are independently mounted on each pedal arm and connected to a common drive shaft in the rear of the bicycle. Each pedal has a hinge point about the level of the seat and each is freely connected via drive chains to a free wheeling sprocket in the rear. A keyed shaft connects all free wheeling sprockets and provides for each sprocket to drive the keyed shaft in one rotational direction. The pedals can return on the back stroke while driving the free wheeling sprocket in reverse, however this rotation will not affect the main sprocket as the keyed shaft will not connect to the free wheeling sprocket at this point.
The motion of the free wheeling sprockets drive the keyed shaft which supplies motion to a main drive sprocket that is the main powering unit. The main drive is then connected by chain, or the like, to the rear wheel or both wheels, as the case may be, and this drives the bicycle. The hand powering unit operates through a separate free wheeling sprocket and is also arranged like a lever in similar manner to the pedals.
The invention also includes the use of a lowered seating arrangement that can be used with the various shifting arrangements described as well as 2 wheel and 3 wheel applications.
It is an object of the invention to position the driver of the bicycle with the body in a low position so that his legs can exert pedal movements with maximum muscle power.
Another object is to provide bicycle drive designs that can maximize the force that the body can exert on the pedals and wheels of the bicycle.
Another object is to provide bicycle drive designs where the user can exert a continuous and sustained level of power throughout the entire power stroke.
Another object is to provide bicycle drive designs where the travel of the wheel is maximized with the least amount of body motion.
Another object is to provide a supplemental source of manual power for a pedal driven bicycle, namely a hand operable unit capable of powering the bicycle through hand powered pumping of unit.
Another object is to allow for the free travel of pedals and pedal arms on the return from the power stroke.
Other advantages will be seen by those skilled in the art once the invention is shown and described.